Explosive safety container



p 14, 1965 M. F T. ZIMMER ETAL 3,206,015

EXPLOSIVE SAFETY CONTAINER Filed D80. 4, 1963 INVENTORS Mari/h F T.Z/'mmer Leo K. Asaoka g, 1

AGENT:

United States Patent 3,206,015 EXPLOSIVE SAFETY (ZONTAINER Martin F. T. Zimmer, La Plata, Md., and Leo K. Asaoka,

San Jose, Calif, assignors to the United States of America as represented by the Secretary of the Navy Filed Dec. 4, 1963, Ser. No. 328,133 12 Claims. (Cl. 20646) (Granted under Title 35, [1.8. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to the safe handling and transportation of explosive materials and more particularly to safety containers therefor.

With the use of more sensitive ingredients in the propellant industry, and particularly in the solid propellant industry, the danger of accidental explosions is greatly increased. Protection for equipment and personnel who must handle these materials in the daily course of their work is therefore necessary. Previously, protection during handling has been afforded by providing safety con tainers for the exposives, but these safety containers have proved inadequate. Metal containers can be built to withstand the force of an explosion but of necessity must be large, heavy and unwieldy. Moreover if a metal container does fracture as a result of an explosion, there is great danger from flying shrapnel. In order to avoid these difliculties and to provide a lighter and more easily handled container, the art has looked for other materials but until the present invention no satisfactory container has been built. Materials such as polyurethane have been tried but this material can withstand detonations of only small quantities of explosive without fracturing.

Accordingly, the primary object of the present invention is the protection of equipment and personnel who handle explosion materials from the blast and shrapnel effects of an accidental explosion by providing a container capable of withstanding such an explosion.

A further object of the invention is to provide a safety container for explosives which is light in weight so as to be easily handled while still being able to withstand the effects of an accidental explosion.

Still a further object of the invention is to provide a safety container for explosives which is inexpensive and easy to fabricate, avoiding the use of large quantities of expensive metals or alloys.

With these objects in view, the present invention employs a block of plastic material having a hole for containing an explosive which hole extends from one face of the block and terminates within the block. The block is made of materials selected from those capable of deforming extensively without fracturing under the influence of rapidly applied strain. A container made in accordance with the teachings contained herein has proved to be capable of withstanding explosions of up to 50 times as much explosive material as could previous similarly sized plastic containers.

Other objects, advantages and novel features of the invention Will become apparent in the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of the preferred embodiment of the container of the present invention; and

FIG. 2 is an elevational view in cross-section of the container of the present invention.

Referring to the drawing, the container is seen to comprise a cylindrical block or body 10. The block has an outer cylindrical side wall 12 and parallel top and bottom walls 14 and 15 respectively.

Opening through top wall 14 is a cylindrical hole or bore defining an inner cylindrical wall 16. The hole is coaxial with wall 12 of block 10 and extends only part way through the block, having its end 18 well short of bottom wall 15 as shown, and the radius thereof is sub stantially less than the radius of the block. The hole serves to contain the explosive being transported as will appear more clearly hereinafter.

The present invention rejects the concept that mere strength is the important characteristic of the material for explosion safety containers. On the contrary, the critical property of such material has been found by the inventors to be the ability of the material to deform extensively without fracturing when subjected to the rapid rate strains such as those accompanying an explosion, and accordingly, block 10 is made from such material. The desired ability to deform is possessed by materials which have good cold flow properties, high tensile strength, and a high percent elongation ability such, for example, as low density ((1910-0940 gm./cc.) polyethylene. Other materials which exhibit the same or similar properties may, of course, be employed. Some that have been tested and found suitable are, polytetrafiuoroethylene, non-rigid forms of polyvinyl plastics, rubber hydrochloride, and vinyl nitrile rubber.

In use the explosive material to be carried is first loaded into a tubular vessel such as a glass or polyethylene tube as suggested at 20 in FIG. 2. The tube is then inserted into the hole in the container. The container is then placed on a conveyance such as a wagon or the like and is normally positioned with its axis at an acute angle, usually 45 to the horizontal and pointed away from the operator of the wagon. The container and explosive can then be safely carried and moved from place to place and in the event of a detonation of the explosive most of the blast will be concentrated axially of the cylinder out of the hole. The container will deform and absorb the blast in directions radially of the container and in the direction of the axis opposite from that of the opening of the hole.

In one highly effective example of the present safety container, low density polyethylene was employed. The dimensions of the containers were as follows: outer diameter 31 cm., length 31 cm., cavity diameter 5 cm., and cavity length 17 cm. This container successfully withstood the detonation of 500 grams of nitroglycerine, a similarly sized container made of polyurethene being able to contain only a 10 gram charge. A smaller container 10 cm. in diameter and length and having a cavity 1.35 cm. in diameter and 7.5 cm. long successfully contained a detonation of 15 grams of nitroglycerine, while a similarly sized polyurethane container could hold only a 2 gram load. Thus, it is apparent that the present invention when constructed of low density polyethylene will hold about 8 times as much explosive for the small container and about 50 times as much for the large container as similarly sized containers constructed of polyurethane, and the objects of the invention have been successfully achieved.

What is claimed is:

1. A container for safe handling and transportation of explosives comprising a block of plastic material having the ability to deform without fracturing when subjected to rapid rate strain, said block having a hole therein, said hole opening centrally through one wall of said block and terminating inside the block well short of the opposite wall thereof, and

an explosive material to be transported disposed within said hole.

2. A container as recited in claim 1, wherein the material of the block is low density polyethylene.

3. A container as recited in claim 1, wherein the material of the block is polytetrafluoroethylene.

4. A container as recited in claim 1, wherein the material of the block is a non-rigid form of polyvinyl plastic. 5. A container as recited in claim 1, wherein the material of the block is a rubber hydrochloride.

' 6. A container as recited in claim 1, wherein the material of the block is vinyl nitrile rubber.

7. A container for safe handling and transportation of explosive comprising a cylindrical block of plastic material which has good cold flow properties, high tensile strength, and high percent elongation ability, said block having a cylindrical bore opening through the center of one end wall thereof, the radius of said bore being substantially less than the radius of said block and said bore terminating in a plane substantially intermediate of the end walls of said block, and an explosive to be transported disposed within said bore. 8. A container as recited in claim 7, wherein the material of the block is low density polyethylene.

9. A container as recited in claim 7, wherein the material of the block is polyeterafluoroethylene.

10. A container as recited in claim 7, wherein the material of the block is a non-rigid form of polyvinyl plastic.

11. A container as recited in claim 7, wherein the material of the block is rubber hydrochloride.

12. A container as recited in claim 7, wherein the material of the block is vinyl nitrile rubber.

References Cited by the Examiner- UNITED STATES PATENTS 64,897 5/67 Moss 217-6 810,060 l/06 Leathers 206-3 1,628,133 5/27 Ferst 2063 2,785,739 3/57 McGregor. 2,797,806 7/57 Davis 20675 2,861,682 11/58 Hatcher 206--75 3,064,801 11/62 Linnell 206--46 3,138,244 6/64 White 206.84 X

FOREIGN PATENTS 19,237 1911 Great Britain. 705,943 3/54 Great Britain.

GEORGE E. LOWRANCE, Acting Primary Examiner.

25 LOUIS G. MANCENE, Examiner. 

7. A CONTAINER FOR SAFE HANDLING AND TRANSPORTATION OF EXPLOSIVE COMPRISING A CYLINDRICAL BLOCK OF PLASTIC MATERIAL WHICH HAS GOOD COLD FLOW PROPERTIES, HIGH TENSILE STRENGTH, AND HIGH PERCENT ELONGATION ABILITY, SAID BLOCK HAVING A CYLINDRICAL BORE OPENING THROUGH THE CENTER OF ONE END WALL THEREOF, THE RADIUS OF SAID BORE BEING SUBSTANTIALLY LESS THAN THE RAIDUS OF SAID BLOCK AND SAID BORE TERMINATING IN PLANE SUBSTANTIALLY INTERMEDIATE OF THE END WALLS OF SAID BLOCK, AND AN EXPLOSIVE TO BE TRANSPORTED DISPOSED WITHIN SAID BORE. 